Today's Message Index:
----------------------
1. 08:46 AM - Re: Revmaster 'dual' alterantors (user9253)
2. 08:58 AM - Revmaster installation manual? (Robert L. Nuckolls, III)
3. 09:18 AM - Re: Re: Revmaster 'dual' alterantors (Robert L. Nuckolls, III)
4. 09:36 AM - Re: Revmaster 'dual' alterantors (Ernest Christley)
5. 10:24 AM - Re: Revmaster installation manual? (user9253)
6. 10:44 AM - Z-11 with 1 slick mag and 1 e-mag (rasmussenRE)
7. 01:19 PM - Brownout Step Up Converter (Sebastien)
8. 01:44 PM - Re: Brownout Step Up Converter (user9253)
9. 02:58 PM - Re: Brownout Step Up Converter (Robert L. Nuckolls, III)
10. 03:02 PM - Re: Z-11 with 1 slick mag and 1 e-mag (Robert L. Nuckolls, III)
11. 03:16 PM - Harley-Davidson 32A r/r (Robert L. Nuckolls, III)
12. 03:42 PM - Re: Revmaster installation manual? (Paul Eckenroth)
13. 04:16 PM - Re: Revmaster installation manual? (Robert L. Nuckolls, III)
14. 05:27 PM - Re: Revmaster installation manual? (Paul Eckenroth)
15. 08:01 PM - Re: Revmaster installation manual? (Robert L. Nuckolls, III)
16. 08:51 PM - How do you turn 13 D-Sub pins into 5 wires? (rparigoris)
17. 08:54 PM - 25 amp slow blow fuse (rparigoris)
18. 09:02 PM - Re: Brownout Step Up Converter (johnbright)
Message 1
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| Subject: | Re: Revmaster 'dual' alterantors |
Using both windings is a good idea.
What about the phase angle between the two windings? Do we know what it is?
Suppose the two windings are 90 degrees out of phase or some other unknown angle.
How will that affect the proposed circuit? Will the peak AC voltage be higher?
Do capacitors help very much to smooth the DC voltage in a power circuit?
It would help to have a Revmaster alternator to play with.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498085#498085
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| Subject: | Revmaster installation manual? |
Does anyone have a .pdf copy of a Revmaster installation
manual for 2300, 3000 engines . . . or both?
If there's a download link for either . . . that would
be fine too.
Thanks!
Bob . . .
Message 3
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| Subject: | Re: Revmaster 'dual' alterantors |
At 10:39 AM 8/31/2020, you wrote:
>
>Using both windings is a good idea.
>What about the phase angle between the two windings? Do we know what it is?
No . . .
>Suppose the two windings are 90 degrees out of phase or some other
>unknown angle.
>How will that affect the proposed circuit? Will the peak AC voltage
>be higher?
Good question.
I doubt they are polyphase . . . you gotta go to a
lot of mechanical fuss to achieve it. It's a function
of stator/magnet ring geometry. They might be different
but it's doubtful. Issue 80 of Contact! magazine has
some nice pictures of the stator arrangement:
http://www.contactmagazine.com/Issue80/Issue-80L.pdf
>Do capacitors help very much to smooth the DC voltage in a power circuit?
They can . . . it's all about current/capacitance ratio
versus frequency. If a capacitor is necessary, it will
be dictated by the CCCV down converter tolerance for
ripple.
>It would help to have a Revmaster alternator to play with.
You got that right!
Bob . . .
Message 4
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| Subject: | Re: Revmaster 'dual' alterantors |
Would this scheme work for other PM generators?=C2- I'm using a 32-amp g
enerator from a Harley-Davidson.=C2- The 74518-88 model regulator for the
se seems to be as plentiful as light bulbs, but I can't find any good detai
ls of what the internals look like.=C2- It has two wire input from the st
ator, and one wire out to the battery positive.=C2- The case serves as gr
ound. No means of control or way to indicate failure, prompting me to build
my own.
On Sunday, August 30, 2020, 10:58:25 PM EDT, Robert L. Nuckolls, III <n
uckolls.bob@aeroelectric.com> wrote:
I've had a few weeks (and road trips) to apply some
'asphalt engineering' effort to a combination of
threads discussing relative fragility of the
Revmaster 'dual' alternators. The latest thread
explored the notion that changing from SLVA to
LiFePO4 was much more likely to burn an alternator winding.
This is not a new topic here on the List . . . found
a few other postings on the same problem.
Without talking to the=C2- designers, it's
difficult to KNOW the original thinking behind the
design. We also cannot know what efforts the factory
has applied to this issue over the years. But I
think we're on pretty firm ground to assert that
the current design is marginal with respect to
thermal robustness.
Alternator windings should be as reliable as
propeller bolts. You might smoke some regulators,
trash some batteries, find yourself wanting for a
few more amps of output . . . but suffering destruction
of the windings suggests the alternator is a weak
link in the system.
Based on the drawing that Dan supplied a few weeks
ago it seems that the designers intended that only
one of the two windings be used at the same time.
I'm guessing that this is a "normal-and-spare"
design philosophy. Therefore, any time a winding fails due
to exceedance of thermal limits, the other winding
was off line.
We don't know the internal configuration of the
recommended rectifier/regulator but it's almost
certain to included silicon controlled rectifier
and one diode in series on each conduction half-
cycle. That's 3, silicon junctions in series
that carry alternator output current.
My current hypothesis suggests that it would be
much better to use BOTH windings all the time. Reduce
the current in each winding by 50% or more. It seems
better to have one configuration that's bulletproof
than two relatively fragile configurations that 'back
each other up'.
Here's the line of reasoning supporting this design
goal. Recall the bits-and-pieces of design? (1)
properties of materials, (2) management of energy
and (3)refinement of process. In this case, our
weak link seems to center on an energy management
issue. Some copper windings are heating past
practical operating limits. This can be either
an insulation failure, wire failure or both.
Properties of Materials:
We know that copper has a pretty significant positive
resistance coefficient for temperature. We observed
this in the temperature vs. current observations
in battery contactors:
https://tinyurl.com/mpcgp3t
https://tinyurl.com/k6bwdqo
We also considered the physics of why an overloaded
wire tends to burn open at the center of a free-air
span.
As copper heats up, resistance goes up, voltage drop
goes up, dissipated energy goes up, temperature rises
some more . . . and you can see where this is headed.
Take this tid-bit of knowledge about copper
wire and consider how many times you've observed or
heard of the windings or lead wires of any system
failing due to overheat.
I've seen some windings burn up on alternators for
reasons OTHER than poor thermal management. I've never
had a winding burn on my car. I've had one short
and start popping fuses . . . but I doubt that it
was due to burned insulation or melted wires!
The point is, ANY configuration that demonstrates
repeated failure to do open wires or cooked insulation
is MARGINAL at best; hazardous at worst.
Okay, how to reduce the load in Revmaster alternator
wires . . . hopefully without compromising ability
to deliver ENERGY into the system. Here's the energy
management consideration:
We know that PM alternators have a checkered history
of performance . . . but mostly due to stone simple
regulators that DO NOT offer active current limiting.
Furhter, many versions use a full wave bridge consisting
of two pairs of junction diode and silicon controlled
rectifiers. Alternator output current flows through
two of these devices with total drop on the
order of 2 volts. 2 volts out of a 14v system is
a substantial proportion of energy . . . something
on the order of 15 to 25 watts that needs to be
managed in those cute little castings . . . but
that's another story.
Harking back to the earliest days of my studies
in electron herding, ac rectifiers were vacuum
tubes (not junctions) and ac power sources were transformers
plugged into the wall (not spinning magnets).
Except for the systems with very low energy
requirements (table top radios), the rectifiers
were dual diodes driven from either side of a
center tapped transformer secondary. This configuration
had some profound effects in thermal management.
EACH diode carries 1/2 the total current. These
devices have considerable resistance . . . watts
I(squared) x R so if you reduce current by 1/2,
watts goes down to 1/4.=C2- Same thing happens in the
transformer secondary . . . the secondary wire
size can be made smaller in a trade off between
energy lost and transformer size.
Refinement of process:
So take a peek at the simplified proposal diagram.
Hook the two Revmaster windings in series-aiding
and bring out the center-tap. Connect in full wave
configuration with only TWO junction rectifiers.
Feed this resulting energy off to a filter capacitor
size to be determined.
This will give us a 'supply voltage' of some value
ideally adjust to about 20VDC at cruise RPM and
alternators full load design point.
This voltage is going to be all over the place
depending on load and engine rpm . . . but that's
the nature of the PM alternator.
Now, let's power condition that energy with a constant
current, constant voltage, switch-mode regulator.
NOW we have a BIG difference in performance:
Voltage is adjustable and controlled by active electronics.
Current is adjustable and limited by active electronics.
I suggest this configuration offers
significant improvement in Revmaster's engine
driven power source. Energy being delivered
to the regulator is at significantly higher than
the output set point, CURRENT in from the alternator
will be LOWER than current delivered by the regulator.
Further, each winding works 1/2 of the time so it
follows that heating effects on each winding are much
reduced from the current configuration.
Silicon junctions in the rectifier are significantly
reduced off-setting some new losses introduced by
the electronic CCCV regulator.
It seems that we could craft an engine driven power
system that almost never fails in exchange for one
that fails too many times and for the wrong reasons.
I'm tied up in some house remodeling and we've
added another grandson to the population of Medicine
Lodge Jr High School . . . so refinement of this idea
will be slow. But I'm building an alternator drive stand,
power supply and load bank out in the mess-making shop. B&C has
provided me with both PM and wound-field test articles.
I have a couple of those CCCV regulators that we discussed
on hand right now. They may not be the right size in all
respects but satisfactory for proof-of-concept experiments. I
already have some LiFePO4 and SLVA batteries on hand.
The pieces are coming together. Comments and considered
critical review are most welcome.
=C2- Bob . . .
Message 5
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| Subject: | Re: Revmaster installation manual? |
Evidently Revmaster offers a 30 amp alternator on new engines.
http://revmasteraviation.com/?tag=cdi-ignition
-
This is not an installation manual, but is a description of the Revmaster
engine that includes a picture of the alternator coils and a brief
description. From CONTACT Magazine.
http://www.revmasteraviation.com/wp-content/uploads/2017/07/Revmaster-R-2300.pdf
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498089#498089
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| Subject: | Z-11 with 1 slick mag and 1 e-mag |
Hi Bob,
Using Z-11 for my RV8 build. Z-11 depicts two traditional mags, and there
are several different switch configurations in the other Z diagrams that
have one mag and one e-mag. Could you tell me which you recommend? Thanks
for all you do.
Regards,
Robert
Message 7
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| Subject: | Brownout Step Up Converter |
My friend has a Harmon Rocket with a GRT EFIS. During start the voltage
sags just enough to mess up the GRT so that it usually needs a reset after
start. Was there ever consensus on a good ebay dc-dc step up converter? I'm
thinking of ordering this one:
https://www.ebay.ca/itm/5A-DC-DC-Boost-Step-up-Volt-Converter-Power-Supply-Module-5V-9V-12V-19V-24V-36V/192243452240
The EFIS needs 1A so this should have no problem keeping up. Any thoughts?
Message 8
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| Subject: | Re: Brownout Step Up Converter |
I don't know if there was ever a recommendation as to which DC-DC
converter to buy, but there are some that cost between $5 and $10 that
have a copper coil and look impressive.
Beware of exaggerated ampacity claims.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498092#498092
Message 9
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| Subject: | Re: Brownout Step Up Converter |
At 03:13 PM 8/31/2020, you wrote:
>My friend has a Harmon Rocket with a GRT EFIS.
>During start the voltage sags just enough to
>mess up the GRT so that it usually needs a reset
>after start. Was there ever consensus on a good
>ebay dc-dc step up converter? I'm thinking of ordering this one:
>
><https://www.ebay.ca/itm/5A-DC-DC-Boost-Step-up-Volt-Converter-Power-Supply
-Module-5V-9V-12V-19V-24V-36V/192243452240>https://www.ebay.ca/itm/5A-DC-DC-
Boost-Step-up-Volt-Converter-Power-Supply-Module-5V-9V-12V-19V-24V-36V/19224
3452240=C2
>=C2
>
>The EFIS needs 1A so this should have no problem keeping up. Any thoughts?
email a shipping address and I'll send
you one to try. I've not had time to characterize
these on the test bench yet. But if we're
picking one based on advertised performance,
this one is as good as any.
Bob . . .
Message 10
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| Subject: | Re: Z-11 with 1 slick mag and 1 e-mag |
At 12:38 PM 8/31/2020, you wrote:
>Hi Bob,
>
>Using Z-11 for my RV8 build. Z-11 depicts two traditional mags, and
>there are several different switch configurations in the other Z
>diagrams that have one mag and one e-mag. Could you tell me which
>you recommend? Thanks for all you do.
>
>Regards,
>
>Robert
I've not reviewed the latest recommendations by
Emagair for their products. Are you using
toggle switches? Wire the Mag per Z-11, the
eMag per manufacturer's instructions.
Which model of eMag are you installing?
Bob . . .
Message 11
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| Subject: | Harley-Davidson 32A r/r |
At 11:29 AM 8/31/2020, you wrote:
>Would this scheme work for other PM generators? I'm using a 32-amp
>generator from a Harley-Davidson. The 74518-88 model regulator for
>these seems to be as plentiful as light bulbs, but I can't find any
>good details of what the internals look like. It has two wire input
>from the stator, and one wire out to the battery positive. The case
>serves as ground. No means of control or way to indicate failure,
>prompting me to build my own.
I've got no reason to believe that the most
ROBUST of PM rectifier/regulators would not
work with the smallest of PM alternators.
You can control ANY rectifier/regulator with
a relay in one of the AC leads out of the
alternator . . . as depicted in many AEC
drawings. LOW Volts warning is your
primary failure warning. 'Real' low volts
warning is built into B&C regulators . . .
most other 'warnings' are driven by less
than elegant sensing systems (including
the venerable VR166).
I would judge your probability of success
to be high.
Bob . . .
Message 12
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| Subject: | Re: Revmaster installation manual? |
Bob
Included is the section from the Revmaster manual that deals with the
generator and CDI ignition. I'm looking forward to more from you on the
Revmaster problem so I can order a new stator and rewire with confidence
that the second time around will be the final time.
Paul
On Mon, Aug 31, 2020 at 12:03 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> Does anyone have a .pdf copy of a Revmaster installation
> manual for 2300, 3000 engines . . . or both?
>
> If there's a download link for either . . . that would
> be fine too.
>
> Thanks!
>
>
> Bob . . .
>
Message 13
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| Subject: | Re: Revmaster installation manual? |
At 05:38 PM 8/31/2020, you wrote:
>Bob
>
>Included is the section from the Revmaster=C2
>manual that deals with the generator and CDI
>ignition. I'm looking forward to more from you
>on the Revmaster problem so I can order a new
>stator and rewire with confidence that the
>second time around will be the final time.
Yeah, I've seen this 'wiring diagram' . . . sad
Everything else I've seen/read about this engine
engenders a lot of confidence. When you pay out
killobux for a modern, strongly promoted engine you
should get something better than this in the way
of installation, performance and system integration.
Can I have your burned stator?
Bob . . .
Message 14
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| Subject: | Re: Revmaster installation manual? |
The stator is still installed in the engine. I am currently flying on
battery only. When the solution to the Revmaster debacle is clear, I will
get a new stator. Replacement of the stator is not trivial as the engine
must be removed from the airframe. However when it is finally removed I
will send it your way if still interested.
Paul
On Mon, Aug 31, 2020 at 7:21 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 05:38 PM 8/31/2020, you wrote:
>
> Bob
>
> Included is the section from the Revmaster=C3=82 manual that deals with t
he
> generator and CDI ignition. I'm looking forward to more from you on the
> Revmaster problem so I can order a new stator and rewire with confidence
> that the second time around will be the final time.
>
>
> Yeah, I've seen this 'wiring diagram' . . . sad
>
> Everything else I've seen/read about this engine
> engenders a lot of confidence. When you pay out
> killobux for a modern, strongly promoted engine you
> should get something better than this in the way
> of installation, performance and system integration.
>
>
> Can I have your burned stator?
>
>
> Bob . . .
>
Message 15
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| Subject: | Re: Revmaster installation manual? |
At 07:22 PM 8/31/2020, you wrote:
>The stator is still installed in the engine.=C2 I
>am currently flying on battery only.=C2 When the
>solution to the Revmaster debacle is clear, I
>will get a new stator.=C2 Replacement of the
>stator is not trivial as the engine must be
>removed from the airframe.=C2 However when it is
>finally removed I will send it your way if still interested.
Sounds like a deal . . .
Do I surmise correctly that you ran one alternator until
it toasted, then ran the second?
Bob . . .
Message 16
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| Subject: | How do you turn 13 D-Sub pins into 5 wires? |
Hi Group I have 13 pins on a D-Sub connector coming from Avionics that need to
go to single point ground firewall field of tabs. I need to turn into ~ 5 wires
that will go to field of tabs. I think I remember seeing how to do this but
can't find it. Thx. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498100#498100
Message 17
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| Subject: | 25 amp slow blow fuse |
Hi Group I need a 25 amp slow blow fuse for my Rotax generator. Anyone know a source?
I would prefer something robust like a slow blow ANL fuse that can be mounted
on stud. Thx. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498101#498101
Message 18
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| Subject: | Re: Brownout Step Up Converter |
In case this is interesting.
Analog Devices offers a demo board manufactured by Linear Technology.
Googling "Demo Circuit 1641A" will find an Analog Devices page with much detail
as well as a Mouser page where it sells for $128.
"Demonstration circuit DC1641 is DC/DC boost converter featuring the LTC3786 constant
frequency current mode boost controller. The DC1641A operates over 5V to
24V input and provides over 5A at 6V input voltage and over 9A of output current
at 10V input as shown in figure 3. The 350kHz constant frequency operation
results in small and efficient circuit. The converter provides high output voltage
accuracy (typically 3%) over wide load range with no minimum load requirement.
The demonstration circuit can be easily modified to generate different
output voltages."
Someone on VAF posted about it: https://vansairforce.net/community/showpost.php?p=1458960&postcount=2
--------
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
https://drive.google.com/drive/folders/1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498102#498102
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